Re: mark_object and hash tables fail to mark all objects?

[Simon Josefsson]

Simon Josefsson <address@hidden> writes:

> When changing mark_object() for Lisp_Process, it occured to me that
> maybe hash tables should be handled the same way as struct window,
> because right now it explicitly marks its members, thereby missing to
> mark count, key_and_value, next_free, next_weak.  Or was there some
> deeper logic in not marking those variables?  Maybe that should be
> stated in a comment.  I haven't tested the patch.

I now see that key_and_value is handled separately.  But the question
remains for the other variables.

> 2002-01-27  Simon Josefsson  <address@hidden>
>
>       * alloc.c (mark_object): Use a for loop instead of explicitly
>       marking members of Lisp_Hash_Table, to fix lack of marking
>       count, key_and_value, next_free, next_weak.
>
> --- alloc.c.~1.259.~  Wed Jan  9 18:04:45 2002
> +++ alloc.c   Sun Jan 27 12:48:08 2002
> @@ -4632,8 +4632,10 @@
>       }
>        else if (GC_HASH_TABLE_P (obj))
>       {
> +       register struct Lisp_Vector *ptr = XVECTOR (obj);
>         struct Lisp_Hash_Table *h = XHASH_TABLE (obj);
>         EMACS_INT size = h->size;
> +       register int i;
>         
>         /* Stop if already marked.  */
>         if (size & ARRAY_MARK_FLAG)
> @@ -4643,16 +4645,12 @@
>         CHECK_LIVE (live_vector_p);
>         h->size |= ARRAY_MARK_FLAG;
>  
> -       /* Mark contents.  */
> -       mark_object (&h->test);
> -       mark_object (&h->weak);
> -       mark_object (&h->rehash_size);
> -       mark_object (&h->rehash_threshold);
> -       mark_object (&h->hash);
> -       mark_object (&h->next);
> -       mark_object (&h->index);
> -       mark_object (&h->user_hash_function);
> -       mark_object (&h->user_cmp_function);
> +       /* There is no Lisp data below the member CMPFN in
> +          struct HASH_TABLE.  Stop marking when that slot is reached.  */
> +       for (i = 0;
> +            (char *) &ptr->contents[i] < (char *) &h->cmpfn;
> +            i++)
> +         mark_object (&ptr->contents[i]);
>  
>         /* If hash table is not weak, mark all keys and values.
>            For weak tables, mark only the vector.  */